South Korea was holding combined live-fire drills with the United States on Thursday in Pocheon, the Yonhap news agency reported.
South Korea’s National Fire Agency said that the bombs were “presumed to have fallen on a village during a South Korea-US joint exercise”.
This resulted in “casualties and property damage, with many displaced residents”, it said, adding that four people had been seriously injured and three suffered minor injuries.
One church building and sections of two houses were damaged, according to the statement.
Joint South Korea-US “Freedom Shield” military exercises, one of the security allies’ largest annual joint exercises, are set to begin later this month.
The two Koreas remain technically at war since the 1950 to 1953 conflict ended in an armistice, not a peace treaty.
The US stations tens of thousands of soldiers in the South, in part to protect Seoul against Pyongyang.
